Fiber optic connectors and fiber optic connection systems

ABSTRACT

The present disclosure relates to a system for making or assembling fiber optic connectors that allows a pre-terminated fiber optic cable to be made compatible with any number of different styles or types of fiber optic connectors or fiber optic adapters. A connector core of the system can be used as a stand-alone connector with a small form-factor adapter.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is being filed on Aug. 24, 2020 as a PCT InternationalPatent Application and claims the benefit of U.S. Patent ApplicationSer. No. 62/891,842, filed on Aug. 26, 2019, and claims the benefit ofU.S. Patent Application Ser. No. 63/003,988, filed on Apr. 2, 2020, thedisclosures of which are incorporated herein by reference in theirentireties.

TECHNICAL FIELD

The present disclosure relates generally to fiber optic connectors. Moreparticularly, the present disclosure relates to systems for making fiberoptic connectors, and fiber optic connectors made from such systems.

BACKGROUND

Fiber optic communication systems are becoming prevalent in part becauseservice providers want to deliver high bandwidth communicationcapabilities (e.g., data and voice) to customers. Fiber opticcommunication systems employ a network of fiber optic cables to transmitlarge volumes of data and voice signals over relatively long distances.Optical fiber connectors are an important part of most fiber opticcommunication systems. Fiber optic connectors allow two optical fibersto be quickly optically connected without requiring a splice. Fiberoptic connectors can be used to optically interconnect two lengths ofoptical fiber. Fiber optic connectors can also be used to interconnectlengths of optical fiber to passive and active equipment.

A typical fiber optic connector includes a ferrule assembly supported ata distal end of a connector housing. A spring is used to bias theferrule assembly in a distal direction relative to the connectorhousing. The ferrule functions to support an end portion of at least oneoptical fiber (in the case of a multi-fiber ferrule, the ends ofmultiple fibers are supported). The ferrule has a distal end face atwhich a polished end of the optical fiber is located. When two fiberoptic connectors are interconnected, the distal end faces of theferrules abut one another and the ferrules are forced proximallyrelative to their respective connector housings against the bias oftheir respective springs. With the fiber optic connectors connected,their respective optical fibers are coaxially aligned such that the endfaces of the optical fibers directly oppose one another. In this way, anoptical signal can be transmitted from optical fiber to optical fiberthrough the aligned end faces of the optical fibers. For many fiberoptic connector styles, alignment between two fiber optic connectors isprovided through the use of an intermediate fiber optic adapter.

Ruggedized (i.e., hardened) fiber optic connection systems include fiberoptic connectors and fiber optic adapters suitable for outsideenvironmental use. These types of systems are typically environmentallysealed and include robust fastening arrangements suitable forwithstanding relatively large pull loading and side loading. Exampleruggedized fiber optic connection systems are disclosed by U.S. Pat.Nos. 7,467,896; 7,744,288 and 8,556,520.

It will be appreciated that a number of different types of ruggedizedfiber optic connectors are available for outside environmental use.International Publication No. WO2015/028433 discloses a system formaking fiber optic connectors in which a number of different ruggedizedouter assemblies having different form-factors or configurations can beselectively mounted on a pre-terminated cable such that thepre-terminated cable can be customized to be compatible with aparticular style or type of fiber optic connector or fiber opticadapter.

SUMMARY

Certain aspects of the present disclosure relate to a system for makingor assembling fiber optic connectors that allows a pre-terminated fiberoptic cable to be made compatible with any number of different styles ortypes of fiber optic connectors or fiber optic adapters. In certainexamples, the system allows the selection of different shrouds, outerhousings, outer fasteners and the like for mounting over a connectorcore that pre-terminates the end of a fiber optic cable. In certainexamples, the different shrouds or outer housings can include differentform factors, different keying arrangements, different shapes, and thelike. Further, the shrouds can be used in combination with differentfastening elements for fastening the final assembled connector toanother fiber optic connector or a fiber optic adapter. Examplefastening elements can include turn-to-secure fasteners (e.g., threadedfasteners and bayonet-style fasteners), slideable fasteners and snap-fitfasteners. In certain examples, different sealing arrangements can beprovided on the different shrouds or housings. In certain examples, theouter shrouds or housings or fasteners can be part of outer connectorassemblies that are preferably hardened/ruggedized. Certain aspects ofthe present disclosure relate to providing a connector core that canalso be used as a small form-factor fiber optic connector that can beused directly (e.g., without any intermediate shroud over the core) incombination with a corresponding small form-factor ruggedized fiberoptic adapter having a form-factor that complements the form-factor ofthe connector core. In certain examples, the connector core includes aseal that is adapted to seal with a shroud of a ruggedized (i.e.,hardened) connector assembly when the core is inserted in the shroud,and is adapted to seal with the small form-factor adapter when theconnector core is mated with the small form-factor adapter. In certainexamples, the connector core includes a turn-to-secure fastener that isadapted to couple with an exterior of a shroud of a ruggedized connectorassembly when the core used with the ruggedized connector assembly, andis adapted to couple with an exterior of the small form-factor adapterwhen the connector core is used directly with small form-factor adapter.

Another aspect of the present disclosure relates to a ruggedized fiberoptic adapter having a small form-factor. In one example, the ruggedizedfiber optic adapter has an elongate main body having a unitary,one-piece molded construction.

A further aspect of the present disclosure relates to a fiber opticadapter including a helical guide feature for rotationally guiding afiber optic connector to a keyed rotational orientation. In one example,the guide feature is capable of rotationally guiding a fiber opticconnector along a rotational range as the fiber optic connector isinserted into the fiber optic adapter. In certain examples, therotational range can include at least 120 degrees, or at least 140degrees, or at least 160 degrees or at least 180 degrees.

A further aspect of the present disclosure relates to a smallform-factor connector core that can be used directly with a ruggedizedsmall form-factor fiber optic adapter.

A variety of additional inventive aspects will be set forth in thedescription that follows. The inventive aspects can relate to individualfeatures and to combinations of features. It is to be understood thatboth the forgoing general description and the following detaileddescription are exemplary and explanatory only and are not restrictiveof the broad inventive concepts upon which the examples disclosed hereinare based.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a fiber optic connector system in accordance with theprinciples of the present disclosure;

FIG. 2 is an exploded view of a connector core of the system of FIG. 1;

FIG. 3 is perspective view of the connector core of FIG. 2;

FIG. 4 is another perspective view of the connector core of FIG. 2;cross-sectional view taken longitudinally through the second fiber opticconnector assembly of FIG. 2;

FIG. 5 is a cross-sectional view taken longitudinally through theconnector core of FIG. 2;

FIG. 6 is an exploded view of a small form-factor fiber optic adapter ofthe system of FIG. 1;

FIG. 7 is perspective view showing a ruggedized port of the smallform-factor fiber optic adapter of FIG. 6 covered by a dust cap;

FIG. 8 is a perspective view showing a non-ruggedized port of the smallform-factor fiber optic adapter of FIG. 6 with a non-ruggedized fiberoptic connector secured therein;

FIG. 9 is a perspective view of a main body of the small form-factorfiber optic adapter of FIG. 6;

FIG. 10 is an end view of the ruggedized port of the small form-factorfiber optic adapter of FIG. 6;

FIG. 11 is a cross-sectional view taken along section line 11-11 of FIG.10;

FIG. 12 is a cross-sectional view taken along section line 12-12 of FIG.10;

FIG. 13 is the cross-sectional view of FIG. 11 with a non-ruggedizedfiber optic connector installed in the non-ruggedized port of the smallform-factor fiber optic adapter;

FIG. 14 depicts a portion of the small form-factor fiber optic adapterof FIG. 6 with internal helical keying guides shown in hidden line;

FIG. 15 is a cross-sectional view showing the connector core and thenon-ruggedized fiber optic connector optically coupled to each other bythe small form-factor fiber optic adapter;

FIG. 16 shows the small form-factor fiber optic adapter of FIG. 6 withthe connector core installed in the ruggedized port and a retentioncollar in a non-retaining position;

FIG. 17 shows the small form-factor fiber optic adapter of FIG. 6 withthe connector core installed in the ruggedized port and the retentioncollar in a retaining position;

FIG. 18 is a perspective view of a turn-to-secure fastener of theconnector core of FIG. 10;

FIG. 19 is another perspective view of the turn-to-secure fastener ofthe connector core or FIG. 10;

FIG. 20 is a further perspective view of the turn-to-secure fastener ofthe connector core or FIG. 10;

FIG. 21 is still another perspective view of the turn-to-secure fastenerof the connector core or FIG. 10;

FIG. 22 is a plan view showing an example interior coupling arrangementof the turn-to secure fastener;

FIG. 23 is a plan view showing an example exterior coupling arrangementadapted to interlock with the interior coupling interface of FIG. 22;and

FIGS. 24-26 depict a sequence of steps for interlocking the interior andexterior coupling arrangements of FIGS. 22 and 23.

DETAILED DESCRIPTION

FIG. 1 illustrates an example fiber optic connector assembly system 20in accordance with the principles of the present disclosure. The fiberoptic connector assembly system 20 allows a pre-terminated fiber opticcable 22 to be readily configured in one of any number of differentconnector configurations. The different connector configurations caninclude connector configurations having different connectorhousings/shrouds, different keying arrangements for keying withdifferent styles or types of fiber optic adapters or fiber opticconnectors, different fasteners compatible with different fiber opticadapters and fiber optic connectors, and the like. In certain examples,the different connector arrangements can include a plurality ofdifferent hardened (i.e., ruggedized) connector arrangements adapted tobe compatible with different styles or types of hardened fiber opticconnectors or hardened fiber optic adapters. It will be appreciated thatthe pre-terminated cable 22 can be fitted with a selected one of thedifferent outer connector arrangements either in the field or in thefactory to render the pre-terminated fiber optic cable compatible with aparticular type of connector system (e.g., the pre-terminated fiberoptic cable with the selected connector assembly mounted thereon iscompatible and mateable with a particular fiber optic adapter styleand/or a particular fiber optic connector style). In certain examples,the pre-terminate cable can include a connector core that is directlycompatible with a fiber optic adapter.

Referring still to FIG. 1, the fiber optic connector assembly system 20includes a connector core 23 terminating one end of the fiber opticcable 22. A turn-to-secure fastener 26 is rotatably mounted on theconnector core 23, and a strain relief boot 28 is mounted on theturn-to-secure fastener 26. The turn-to-secure fastener 26 mounts on theconnector core 23 adjacent a rear end of the connector core (i.e.,adjacent at end to which the cable is secured). A seal 30 is mounted onthe connector core 23 within an interior of the turn-to-secure fastener26 (see FIG. 5). The fiber optic connector assembly system 20 alsoincludes a number of different components, arrangements, assemblies orthe like that can be selected and individually mounted on the connectorcore 23 and secured to the connector core 23 by the turn-to-securefastener 26. The seal 30 can be configured to seal against thecomponents, arrangements or assemblies when the components, arrangementsor assemblies are coupled to the connector core 23. The variouscomponents, arrangements, and assemblies are depicted as including adust cap 32 (see FIG. 2), a first hardened connector shroud and fastenerarrangement 34, a second hardened connector shroud and fastenerarrangement 36, and a small form-factor fiber optic adapter 38 having atleast one ruggedized port for directly receiving the connector core 23.

It will be appreciated that the dust cap 32 can be secured over theconnector core 23 to protect the connector core 23 and the terminatedoptical fiber or fibers supported thereby prior to coupling theconnector core with any of its mating components such as the firstarrangement 34, the second arrangements 36 or the small form-factorfiber optic adapter 38. It will be appreciated that the dust cap 32 isrequired to be removed from the connector core 23 prior to coupling theconnector core with any of its mating components.

A first fiber optic connector assembly that results when the firsthardened connector shroud and fastener arrangement 34 is mounted on theconnector core 23 is compatible and mateable with a FastConnect™ fiberoptic adapter 41 (shown schematically at FIG. 1) sold by HuaweiTechnologies Company Ltd. (see U.S. Pat. No. 9,557,493, which is herebyincorporated by reference in its entirety). A second fiber opticconnector assembly that results when the second hardened connectorshroud and fastening arrangement 36 is mounted on the connector core 23is configured to be compatible with an Opti Tap™ fiber optic adapter 43(shown schematically at FIG. 1) by Corning Cable Systems LLC (e.g., seeU.S. Pat. No. 7,090,407, which is hereby incorporated by reference inits entirety). The small form-factor fiber optic adapter 38 includes aruggedized port 39 adapted to directly receive the connector core 23without requiring the use of an intermediate shroud for keying,alignment or sealing.

It will be appreciated that a fiber optic cable is pre-terminated bymounting a structure at the end of the cable that presents the opticalfiber or fibers for optical connection by a de-mateable opticalconnection. For example, a fiber optic cable can be pre-terminated bymounting a ferrule at the end of the optical fiber or fibers of thecable in preparation for presenting the optical fiber as part of aferruled optical connector. In other examples, a housing or otherstructure can be attached to the fiber optic cable and can function toalign or position the optical fiber without the use of a ferrule as inthe case of a ferrule-less fiber optic connector. In the depictedexample, the fiber optic cable 22 is pre-terminated by mounting theconnector core 23 at the end of the fiber optic cable 22 prior toassembling any of the hardened arrangements 34, 36 over the connectorcore 23.

Referring to FIG. 3, the connector core 23 includes a connector corehousing 24 that is elongated along a length that extends along alongitudinal axis 50. The connector core housing 22 includes a frontplug end 52 positioned opposite from a rear cable attachment end 54. Thefront plug end 52 optionally has a form factor compatible with an SCtype fiber optic adapter, but could have other form factors as well suchas an LC connector form factor compatible with an LC fiber opticadapter. The fiber optic cable 22 is attached or secured to connectorcore 23 at the rear cable attachment end 54 of the connector corehousing 24. For example, strength members (e.g., yarn type strengthmembers such Aramid yarn or fiberglass) can be attached to the connectorcore 23 at the rear cable attachment end 54 by adhesive (e.g., epoxy),crimping or other means. The fiber optic cable 22 includes an outerjacket 56. The outer jacket 56 of the fiber optic cable 22 can besecured to the cable attachment end 54 of the connector core housing 24by a sleeve 57 such as a shape memory sleeve (e.g., a heat-shrinksleeve). In certain examples, the heat-shrink sleeve can include aninterior layer of adhesive for bonding the heat-shrink sleeve to theouter jacket 56 and to the connector core housing 24. The turn-to-securefastener 26 is mounted over the connector core housing 24 and can beturned (e.g., rotated) relative to the connector core housing 24 aboutthe longitudinal axis 50. The turn-to-secure fastener 26 is capturedaxially between an outer stop 47 (e.g., a shoulder) of the housing 24and the front end of the sleeve 57 such that the fastener 26 is retainedon the housing 24. The boot optionally can be turned in unison with thefastener 26 about the axis 50.

An optical fiber structure 58 includes a first section 60 routedlongitudinally through the outer jacket 56 of the fiber optic cable anda second section 62 routed through the connector core body 24. Thesecond section 62 of the optical fiber structure 58 defines a fiber tip64 at the front plug end 52 of the connector core body 24. A frontportion of the second section 62 of the optical fiber structure 58 issecured and supported within a ferrule 66. The ferrule 66 is springbiased in a forward direction relative to the connector core body 24 bya spring 68. An inner body 67 mounts within the connector core body 24and includes a front end 69 that functions as a spring stop and a rearend 71 that can include structure for use in securing strength membersof the fiber optic cable 22 to the connector core 23.

In the case where the ferrule 66 is directly mounted on the opticalfiber of the fiber optic cable 22, the optical fiber structure 58 is anuninterrupted length of optical fiber where the first and secondsections 60, 62 are all part of one continuous optical fiber. In asplice-on version of the connector arrangement, the first section 60 canbe formed by a segment of optical fiber that is optically spliced (e.g.,fusion spliced) to an optical fiber of the fiber optic cable 22 whichforms the second section 62. In certain examples, optical splice can belocated within the interior of the connector core body 24.

The connector core housing 24 includes the exterior stop 47 (e.g., aprojection, a wall, rib, a shoulder or the like) positioned adjacent thecable attachment end 54 of the connector core housing 24. The stop 47can include a forwardly facing positive stop surface 72 and a rearwardlyfacing positive stop surface 74. The surface 74 provides for axialretention of the fastener 26, while the surface 72 provides a positivestop adapted for engaging a corresponding stop surface 75 of the smallform-factor fiber optic adapter 38 for stopping insertion of theconnector core 23 into the small form-factor adapter 38 at apredetermined, fully-inserted location.

The turn-to-secure fastener 26 includes an interior coupling arrangement27 (see FIGS. 18-21) adapted to couple with mating exterior couplingarrangement provided at components adapted to be coupled to theconnector core 23. In certain examples, the interior and exteriorcoupling arrangements can include threaded configurations, bayonet-styleconfigurations, and other interlock configurations. The interlockconfigurations can include configurations that interlock by snap-fitactions and configurations having stops that are rotated fromnon-overlapped positions to overlapped positions in which interferencebetween the stops provide for axial retention of the turn-to-securefastener 26.

The interior coupling arrangement 27 (see FIGS. 18-21) of the fastener26 is adapted to couple with mating exterior coupling arrangements 80-83that respectively correspond to the first hardened connector shroud andfastener arrangement 34, the second hardened connector shroud andfastener arrangement 36, the small form factor adapter 38 and the dustcap 32. The exterior coupling arrangements 80-82 are shown at FIG. 1 andthe exterior coupling arrangement 83 is shown at FIG. 2. The couplinginterface formed between the interior and exterior coupling arrangementspreferably provides two different interlock functions.

The first interlock function is adapted to inhibit rotation between theturn-to-secure fastener 26 and the corresponding mated exterior couplingarrangement. The first interlock function can be provided by a snap-fitarrangement. The snap-fit arrangement may provide a permanent interlockor a multi-use interlock. In the case of a permanent interlock, asnap-fit connection between the interior and exterior couplingarrangements is required to be broken to rotate the turn-to-securefastener 26 from an interlocked rotational position (e.g., a coupledrotational position) to a non-interlocked position (e.g., a non-coupledrotational position). In contrast, if the snap-fit arrangement isadapted for multiple uses, the snap-fit arrangement can function as adetent that encourages the turn-to-secure fastener 26 to remain in aninterlocked rotational position, but with sufficient torque allows thesnap-fit arrangement to be disengaged without breaking the snap-fitarrangement to allow the turn-to-secure fastener 26 to be moved from theinterlocked position to a non-interlocked position.

The second interlock function provided when the interior couplingarrangement 27 is mated with a corresponding one of the exteriorcoupling arrangements 80-83 relates to providing axially securement ofthe fastener 26. When the interior and exterior coupling arrangementsare interlocked, the coupling arrangements are adapted to prevent thefastener 26 from being axially disengaged from the correspondingcomponent to which the fastener 26 is coupled. The portions of thecoupling arrangements that provide the axial retention function caninclude a plurality of stops that interlock (e.g., overlap) with respectto one another when the fastener 26 is rotated to a coupled rotationalposition such that interference between the interlocked stops preventsthe fastener 26 from being axially removed from the correspondingcomponent to which the fastener 26 is coupled.

Referring to FIGS. 18-22, the interior coupling arrangement 27 includesa plurality of ramped snap-fit features 86 spaced uniformly about acentral axis 88 of the fastener 26. Each of the snap-fit features 86includes a ramp surface 90 and a stop surface 92. The interior couplingarrangement 27 also includes an axial retention arrangement 94 includinga plurality of axial stops 96 spaced uniformly about the central axis88. For ease of explanation, FIG. 22 shows the fastener 26 cut along itslength and laid flat such that the entire circumference C of theinterior of the fastener 26 is visible in plan view. The axial stops 96include stop surfaces 98.

FIG. 23 depicts an example exterior coupling arrangement 100 that can berepresentative of the coupling arrangements 80-83. At FIG. 23, thecoupling arrangement has been cut and laid flat such that entire outercircumference of the coupling arrangement 100 is shown in plan view. Theexternal coupling arrangement 100 includes snap-fit features 102 spacedapart from one another along the circumference C. The snap-fit features102 can include catch elements or stops adapted to work in combinationwith the snap-fit features 86 of the interior coupling arrangement. Incertain examples, the snap-fit features 102 can be detent features suchas bumps. In other examples, the snap-fit features 102 can includelatches such as beams. The beams can be configured to have a break-awayfunction to allow movement of the turn-to-secure fastener 26 from acoupled rotational position to an un-coupled rotational position. Inother examples, the snap-fit features 102 provide resistance to rotatingthe turn-to-secure fastener 26 from the coupled rotational position tothe non-coupled rotational position, but that merely deform withoutbreaking to allow movement of the turn-to-secure fastener 26 from thecoupled rotational position to the non-coupled rotational position. Theexterior coupling arrangement 100 also includes an axial retentionarrangement 104 adapted to axially retain the turn-to-secure fastener 26when the turn-to-secure fastener 26 is in the coupled rotationalposition. The axial retention arrangement 104 can include a plurality ofaxial stops 106 (e.g., triangular projections) spaced uniformly alongthe circumference C of the external coupling arrangement 100.

FIGS. 24-26 depict a sequence of steps for coupling together theinterior coupling arrangement 26 and the exterior coupling arrangement100. As shown at FIG. 24, the interior coupling arrangement 27 isaligned with the exterior coupling arrangement 100. FIG. 25 shows theinterior and exterior coupling arrangements 27 from 100 inserted axiallytogether, but in a non-coupled rotational position. FIG. 26 shows theinterior and exterior coupling arrangements 27, 100 rotated from thenon-coupled rotational position to a coupled rotational position. In thecoupled rotational position of FIG. 26, the axial retention stops 106 ofthe external coupling arrangement 100 interlock with and oppose the stopsurfaces 98 of the axial stops 96 of the internal coupling arrangementsuch that interference between the stops 96, 106 prevents theturn-to-secure fastener 26 from being axially disengaged from theexterior coupling arrangement 100 in a removal direction 107 is oppositefrom an insertion direction 108. Additionally, when the turn-to-securefastener 26 is rotated from the non-coupled rotational position to thecoupled rotational position, the snap-fit features 86 snap-past thesnap-fit features 102 of the exterior coupling arrangement 100 such thatopposition between a stop surface 103 of the snap-fit feature 102 andthe stop surface 92 of the snap-fit feature 86 to prevents or resistsmovement of the turn-to-secure fastener 26 from the coupled rotationalposition to the un-coupled rotational position. Further disclosure ofthe coupling arrangements can be found in U.S. Provisional PatentApplication 62/849,760, which is hereby incorporated by reference in itsentirety.

Referring to FIG. 1, the first hardened connector shroud and fastenerarrangement 34 includes a shroud 182 adapted to mount over the core 23and a fastening member 140 that rotationally mounts over the shroud 182.The seal 30 seals between the outside of the core 23 and the inside ofthe shroud 182 when the core 23 is inserted in the shroud 182. Thefastening member 140 is depicted as an outer housing having abayonet-type interface (e.g., bayonet pins) adapted to engage withbayonet slots of the corresponding fiber optic adapter 41 when the fiberoptic connector assembly (i.e., the assembly including the core 23 andthe arrangement 34) is coupled to the fiber optic adapter 41. The shroud182 includes a keying structure in the form of a slot 143 that mateswith a corresponding projection in the fiber optic adapter 41 when thefiber optic connector assembly 40 is mated with the fiber optic adapter.In this way, the keying structure ensures that the fiber optic connectorassembly is inserted into the fiber optic adapter at a desiredrotational orientation. The turn-to-secure fastener 26 is adapted fitover the rear end of the shroud 182 and interlock with the couplingarrangement 80 to couple the connector core 23 to the shroud 182 suchthat the fastener 26 axially retains the core 26 within the shroud 182.

Referring still to FIG. 1, the second hardened connector shroud andfastener arrangement 36 includes a shroud 184 and an outer fasteningmember 145 depicted as a coupling nut having external threads. The seal30 seals against the inside of the shroud 184 when the core 26 issecured in the shroud 184. The shroud 184 includes a pair of frontpaddles 147 adapted to provide a keying function for rotationallyaligning the fiber optic connector assembly (i.e., the assembly whichincludes the core installed within the arrangement 36) within thecorresponding fiber optic adapter 43. The exterior threads of the outerfastening member 145 are adapted to engage with corresponding interiorthreads of the fiber optic adapter 43 to secure the fiber opticconnector assembly within the fiber optic adapter 43. The turn-to-securefastener 26 is adapted fit over the rear end of the shroud 184 andinterlock with the coupling arrangement 81 to couple the connector core23 to the shroud 184 such that the fastener 26 axially retains the core26 within the shroud 184.

Referring to FIGS. 3 and 4, the front plug end 52 of the connector core23 has a form factor compatible with the fiber optic adapter 41, thefiber optic adapter 43 and the small form-factor adapter 38. While thefront plug end 52 is compatible with the fiber optic adapters 41, 43,the first and second hardened connector shroud and fastener arrangements34, 36 are respectively needed to secure and seal the connector core 23within the fiber optic adapters 41, 43. In contrast, the connector core23 can be installed directly within the small form-factor adapter 38without any intermediate shrouds and without requiring any fasteners inaddition to the turn-to-secure fastener 26. Specifically, when theconnector core 23 is secured within the small form-factor adapter 38,the seal 30 forms a seal with the small form-factor adapter 38 and theturn-to-secure fastener 26 couples directly to coupling arrangement 82of the small form fiber optic adapter 38.

Referring to FIGS. 3 and 4, the front plug end 52 includes a pluralityof flats 200 a-200 d positioned about the exterior of the core housing24. Flats 200 a and 200 c are positioned opposite from one another,while flats 200 b and 200 d are position opposite from one another.Flats 200 a, 200 c extend rearwardly from the front end of the corehousing 24 for a substantial length of the total length of the corehousing 24. In one example, the flats 200 a, 200 c extend along at least20% of a total length of the core housing 24. Flat 200 a extends fromthe front end of the core housing 24 to an elongate key 202. Theelongate key 202 is depicted as a rail that projects outwardly from anexterior of the main body of the core housing 24. In one example, thekey 202 has a length that extends from the flat 200 a rearwardly toadjacent the seal 30. In one example, the elongate key extends along atleast 25 percent of the total length of the core housing 24.

The seal 30 is preferably positioned rearward of a longitudinal midpointof the core housing 24. Preferably, the seal 30 is positioned closer tothe rear end of the core housing 24 then the front end of the corehousing 24. In a preferred example, the seal 30 is positioned rearwardof at least two thirds of a total length of the core housing 24. Asdepicted at FIG. 5, the seal 30 is positioned within an interior of theturn-to-secure fastener 26.

The flats 200 b, 200 d are substantially shorter in length then theflats 200 a, 200 c. As depicted at FIG. 3, the flats 200 b, 200 d arepositioned opposite from one another and define the sides that extendbetween the flats 200 a, 200 c.

The coupling arrangements 80, 81 provided on the shrouds 182, 184 of thefirst and second hardened connector shroud and fastener arrangements 34,36 can have a configuration like the external coupling arrangement 100shown at FIG. 23. For example, as shown FIG. 1, the exterior couplingarrangements 80, 81 each include the axial retention arrangement 104including the plurality of the axial retention stops 106 (e.g.,triangular stops) that are positioned circumferentially about theexteriors of the shrouds 182, 184 adjacent the rear ends of the shrouds182, 184. The exterior coupling arrangements 80, 81 also includessnap-fit features 102 a. In the depicted example, the snap-fit features102 a include flexible beams having opposite ends integrated with theshrouds 182, 184 and open spaces beneath the beams. In other example,cantilever style beams could be used. The beams can be orientedtransverse to the circumferential direction (as shown) or parallel tothe circumferential direction.

When the turn-to-secure fastener 26 is inserted axially over theexterior coupling arrangements 80, 81 and then turned from thenon-coupled rotational portion to the coupled rotational position, theramp surfaces 90 of the snap-fit features 86 of the turn-to-securefastener 26 ride over the snap-fit features 102 a causing the features102 a to deflect radially inwardly to allow the snap-fit features 86 tomove past the snap-fit features 102 a. When the turn-to-secure fastener26 reaches the coupled rotational position the snap-fit features 86concurrently move past the snap-fit features 102 a such that thesnap-fit features 102 a elastically return to their non-deflectedposition. In the non-deflected position, opposition between the stopsurfaces 92 of the snap-fit features 86 and the snap-fit features 102 aprevents the turn-to-secure fastener 26 from being rotated from thecoupled rotational position back to the non-coupled rotational position.In the coupled rotational position, the stops 96 of the turn-to-securefastener 26 oppose the axial stops 106 to prevent the fastener 26 frombeing axially disengaged. If sufficient torque is applied to theturn-to-secure fastener 26, the snap-fit features 102 a will breakthereby allowing the turn-to-secure fastener 26 to be rotated from thecoupled rotational position back to the non-coupled rotational position.It will be appreciated that the exterior coupling arrangement 81 on theshroud 184 of the second hardened connector shroud and fastenerarrangement 36 has the same configuration as the exterior couplingarrangement 80. Thus, the core 23 can be attached to the first andsecond hardened connector shroud and fastener arrangements 34, 36 in thesame manner. In other examples, the snap-fit features 102 a may beconfigured for multiple uses.

FIGS. 6-14 depict the small form-factor adapter 38. The smallform-factor adapter 38 is adapted to mount within a mounting opening210. In certain examples, mounting opening 210 can be defined in apanel, through the wall of an enclosure, or in another structure.Preferably, the mounting opening 210 is relatively small in size. In oneexample, mounting opening 210 has an area less than or equal to 150square millimeters. It will be appreciated that the small form-factoradapter 38 has a length L that is relatively long when taking intoconsideration the relatively small area of the mounting opening 210. Incertain examples, the ratio of the area of the mounting opening 210 inmillimeters and the length L of the small form-factor adapter 38 inmillimeters is less than or equal to 3.

Referring to FIG. 6, the small form-factor 38 includes a main adapterbody 212 having a first end 214 and a second end 216. The length L ofthe small form-factor adapter 38 extends between the first and secondends 214, 216. The first end 214 defines a ruggedized connector port 218and can be referred to as a ruggedized end. The second end 216 defines anon-ruggedized connector port 220 and can be referred to as anon-ruggedized end. In certain examples, the adapter main body 212 canhave a one-piece molded construction. The ruggedized connector port 218can be configured to receive the connector core 23 and preferably has aform factor that matches or is otherwise compatible with the form factorof the connector core 23. The non-ruggedized connector port 220 isadapted to receive a non-ruggedized fiber optic connector such as an SCconnector 222.

The main adapter body 212 includes an internal sleeve holder 224. Incertain examples, the internal sleeve holder 224 can contain a ferrulealignment sleeve such as a split-sleeve 225 made of an elastic material(e.g., phosphor bronze, zirconia ceramic, etc.). In certain examples,the internal sleeve holder 224 can include a plurality of fingers thatcan be flexed open to allow the split sleeve to be inserted within andretained inside the internal sleeve holder 224.

When the non-ruggedized fiber optic connector 222 is secured in thenon-ruggedized connector port 220 and the connector core 223 is securedwithin the ruggedized connector port 218, the connector core 23 andnon-ruggedized fiber optic connector 222 are optically connectedtogether. For example, a ferrule 228 of the non-ruggedized fiber opticconnector 222 can be received within one end of the ferrule alignmentsleeve housed within the sleeve holder 224, and the ferrule 66 of theconnector core 23 can be received within the opposite end of the ferrulealignment sleeve housed within the sleeve holder 224 such that the fiberalignment sleeve coaxially aligns the two ferrules 228, 66 to provide anoptical connection between the optical fibers held by each of theferrules 228, 66.

The second end 216 of the main adapter body 212 includes integratedlatches 230 for retaining the non-ruggedized fiber optic connector 222within the non-ruggedized connector port 220. The main adapter body 212also includes an outer flange 232 and exterior threads 234. When themain adapter body 212 is secured within the mounting opening 210 definedby a structure such as a panel 236, the flange 234 engages a first side236 a of the panel 236 while a nut 238 is threaded on the outer threads232 and engages a second side 236 b of the panel. In this way, the panel236 is compressed between the outer flange 232 and the nut 238 to securethe main adapter body 212 to the panel 236.

A seal 240 can be pressed between the flange 232 and the first side 236a of the panel 236. In one example, the seal 240 can be integrated witha lanyard 242 used to couple a dust cap 244 to the main adapter body212. The dust cap 244 is adapted to be secured over the first end 214 ofthe main adapter body 212 to enclose the ruggedized connector port 218prior to inserting the connector core 23 therein. It will be appreciatedthat the dust cap 244 can be removed from the first end 214 of the mainadapter body 212 to allow insertion of the connector core 23 into theruggedized connector port 218. It will also be appreciated that the dustcap 244 can include an internal coupling arrangement of the type shownat FIG. 22 that is adapted to couple with the exterior couplingarrangement 82 provided adjacent the first end 214 of the main adapterbody 212.

Referring to FIGS. 11-14, the main adapter body 212 includes a keyway250 for receiving the elongate key 202 of the connector core 23. Themain adapter body 212 also includes internal structure for rotationallyguiding the keying rail to the keyway 250. In certain examples, thestructure for providing rotational guiding can include two helicalshoulders 252 a, 252 b that rotate in opposite helical directions abouta central longitudinal axis 253 of the main adapter body 212 as theshoulders 252 a, 252 b extend along the axis 253 in a direction from thefirst end 214 to the second end 216 of the main adapter body 212. Incertain examples, the helical guiding shoulders 252 a, 252 b provide forrotational guiding of the connector core 23 as the connector core 23 isinserted into the ruggedized connector port 220 along a rotational rangeof movement of at least 90 degrees, or at least 135 degrees, or at least170 degrees, or about 180 degrees. As depicted, the helical shoulders250 a, 250 b start adjacent of the bottom ruggedized connector port 220and helically rotate approximately 180 degrees in opposite directionsuntil the shoulders meet adjacent the keyway 250 at the top of theruggedized connector port 218. In this way, the helical shoulders 252 a,252 b are configured to rotationally guide the connector core 23 towardthe keyway 250 as via contact with the key 202 to rotationally guide thekey 202 to the keyway 250 regardless of the rotational orientation theconnector core 23 is initially inserted into the ruggedized connectorport 218.

As indicated above, the first end 214 of the main adapter body 212includes the exterior coupling arrangement 82. In the depicted example,the exterior coupling arrangement 82 includes an axial retentionarrangement of the type depicted by the exterior coupling arrangement100. For example, a plurality of the axial stops 106 are provided aboutthe circumference of the main adapter body 212. The exterior couplingarrangement 82 also includes a snap-fit feature 102 b adapted to engagethe snap-fit feature 86 of the turn-to-secure fastener 26 to retain theturn-to-secure fastener 26 in the coupled rotational orientation. In thedepicted example, the snap-fit feature 102 b is a detent (e.g., a bump)over which the snap-fit feature 86 rides as the turn-to-secure fastener26 is rotated relative to the exterior coupling arrangement 82 from thenon-coupled rotational position to the coupled rotational position. Itwill be appreciated that the snap-fit feature 102 b is a detent havingangled surfaces on both sides. Thus, the configuration of the snap-fitfeature 102 b allows the turn-to-secure fastener 26 to be rotated fromthe coupled rotational position back to the non-coupled rotationalposition when sufficient torque is applied to the force the snap-fitfeature 86 of the turn-to-secure fastener 26 back over the snap-fitfeature 102 b. Preferably, the snap-fit feature 102 b does not breakwhen the turn-to-secure fastener 26 is rotated from the coupledrotational position back to the non-coupled rotational position.Instead, flexing of the turn-to-secure fastener 26 and/or the snap-fitfeature 102 b allows the turn-to-secure fastener 26 to be moved from thecoupled rotational position back to the non-coupled rotational position.

In certain examples, the small form-factor adapter 38 further includes aretention collar 300 that mounts over the exterior of the main adapterbody 212 adjacent the first end 214. The retention collar 300 isnon-rotatably mounted relative to the main adapter body 212 such thatthe retention collar 300 cannot be rotated about the central axis of themain adapter body 212. The retention collar 300 is moveable between anextended position (see FIG. 17) and a retracted position (see FIG. 16).A detent 302 is provided for retaining the retention collar 300 in theextended position and in the retracted position. When the retentioncollar 300 is moved to the extended position while the turn-to-securefastener 26 is in the coupled rotational position relative to theexterior coupling arrangement 82, retaining member 305 (e.g., fingers)inside the retention collar 300 extend within the interior of theturn-to-secure fastener 26 and oppose the stop surfaces 92 of theinterior coupling arrangement of the turn-to-secure fastener 26. In thisway, the retention collar 300 prevents the turn-to-secure fastener 26from being rotated from the coupled rotational position back to thenon-coupled rotational position. In contrast, when the retention collar300 is moved to the retracted position, the retaining members 305disengage from the stop surfaces 92 thereby allowing the turn-to-securefastener 26 to be rotated from the coupled rotational position back tothe non-coupled rotational position when sufficient torque is applied tothe turn-to-secure fastener 26 to overcome the detent 102 b and move theturn-to-secure fastener 26 from the coupled rotational position back tothe non-coupled rotational position.

In certain examples, the retention collar 300 can be spring biasedtoward the extended position. In this way, the retention collar 300 canautomatically move from the retracted position to the extended positiononce the fastener 26 is turned from the non-coupled rotational state tothe coupled rotational state. To de-couple the fastener 26, the collar300 can be manually slid from the extended position the retractedposition against the bias of the spring to allow for rotation of thefastener 26 from the coupled rotational state to the non-coupledrotational state. Insertion of the core assembly into the adapter 38 cancause movement of the collar 300 from the extended position to theretracted position (e.g., via physical contact between the retainingsleeve and the core assembly) against the bias of the spring.

1. A fiber optic connector system comprising: an connector coreincluding a front end defining a plug portion and rear end defining acable anchoring location, the connector core including a core seal; afirst ruggedized exterior assembly configured to be mounted over theconnector core, the first ruggedized exterior assembly including a firstshroud configured to be mounted in over the connector core with the coreseal providing sealing between the connector core and the first shroud,the first shroud having a forward end that includes a first keyingarrangement for rotationally keying the first shroud relative to a firstruggedized fiber optic adapter, the first ruggedized exterior assemblyalso including a first ruggedized fastening element for securing thefirst ruggedized exterior assembly to the first ruggedized fiber opticadapter, the first shroud having a first exterior coupling arrangementat an exterior of the first shroud adjacent a rear end of the firstshroud; a second ruggedized exterior assembly configured to be mountedover the connector core, the second ruggedized exterior assemblyincluding a second shroud configured to be mounted over the connectorcore with the core seal providing sealing between the connector core andthe second shroud, the second shroud having a forward end that includesa second keying arrangement for rotationally keying the second shroudrelative to a second ruggedized fiber optic adapter, the first keyingarrangement having a different keying configuration than the secondkeying arrangement, the second ruggedized exterior assembly alsoincluding a second ruggedized fastening element for securing the secondruggedized exterior assembly to the second ruggedized fiber opticadapter, the first ruggedized fastening element having a differentfastening configuration than the second ruggedized fastening element,the second shroud having a second exterior coupling arrangement at anexterior of the second shroud adjacent a rear end of the second shroud;the first ruggedized exterior assembly being usable in combination withthe connector core to make the fiber optic connector system compatiblewith the first ruggedized fiber optic adapter; the second ruggedizedexterior assembly being usable in combination with the connector core tomake the fiber optic connector system compatible with the secondruggedized fiber optic adapter; the connector core having a form factorthat complements a form factor of a third ruggedized fiber optic adaptersuch that the connector core is directly compatible with the thirdruggedized fiber optic adapter without using a ruggedized exteriorassembly, the core seal providing sealing between the third ruggedizedfiber optic adapter and the connector core when the connector core isinserted in the third ruggedized fiber optic adapter, the thirdruggedized fiber optic adapter including a third exterior couplingarrangement at an exterior of the third ruggedized fiber optic adapter;and a turn-to-secure fastener carried with the connector core for: a)coupling the connector core to the first shroud by inserting theturn-to-secure fastener over the rear end of the first shroud andcoupling the turn-to-secure fastener with the first exterior couplingarrangement by turning the turn-to-secure fastener relative to the firstshroud; b) coupling the connector core to the second rear shroud byinserting the turn-to-secure fastener over the rear end of the secondshroud and coupling the turn-to-secure fastener with the second exteriorcoupling arrangement by turning the turn-to-secure fastener relative tothe second shroud; and c) coupling the connector core to the thirdruggedized fiber optic adapter by inserting the turn-to-secure fastenerover the exterior of the third ruggedized adapter and coupling theturn-to-engage fastener with the third exterior coupling arrangement byturning the turn-to-engage fastener relative to the third ruggedizedadapter.
 2. The fiber optic connector system of claim 1, wherein thefirst keying arrangement includes paddles and the second keyingarrangement includes an open ended slot.
 3. The fiber optic connectorsystem of claim 1, wherein the first ruggedized fastening elementincludes a threaded coupling nut and the second ruggedized fasteningelement includes a bayonet-style fastening sleeve.
 4. The fiber opticconnector system of claim 1, wherein a cable is anchored to the rear endof the connector core, wherein an optical fiber of the cable issupported by a ferrule positioned at the plug portion of the connectorcore, and wherein a shape-memory, heat shrink sleeve provides a sealbetween the cable and the connector core.
 5. The fiber optic connectorsystem of claim 1, wherein the connector core includes a core housingthat extends from the front end to the rear end, and wherein theconnector core includes an elongate keying rail that projects radiallyoutwardly from a main body of the core housing and extends along atleast 25 percent of a total length of the core housing.
 6. The fiberoptic connector system of claim 5, wherein a forward end of the rail isoffset from the front end of the core housing, and a rearward end of therail is located adjacent the core seal.
 7. The fiber optic connectorsystem of claim 6, wherein the main body of the core housing defines aflat that extends from the forward end of the rail to the front end ofthe core housing along at least 20 percent of the total length of thecore housing.
 8. The fiber optic connector system of claim 1, whereinthe core seal is positioned rearward of a longitudinal midpoint of theconnector core.
 9. The fiber optic system of claim 1, wherein the firstand second exterior coupling arrangements have a first configuration,and the third exterior coupling arrangement has a second configurationdifferent from the first configuration.
 10. The fiber optic system ofclaim 9, wherein the first configuration is adapted for one-time usewith the turn-to-secure fastener and the second configuration allows formultiple uses with the turn-to-secure fastener.
 11. The fiber opticsystem of claim 10, wherein the first configuration includes a snap-fitretaining element that retains the turn-to-secure fastener in a coupledstate with respect to the first or second shroud, and is required to bebroken to rotate the turn-to-secure fastener from the coupled state to anon-coupled state.
 12. The fiber optic system of claim 11, wherein thesecond configuration includes a detent retaining element that retainsthe turn-to-engage fastener in a coupled state with respect to the thirdruggedized fiber optic adapter, but that allows the turn-to-securefastener to be rotated from the coupled state to a non-coupled statewithout requiring breaking of the detent retaining element.
 13. A fiberoptic connection apparatus comprising: a connector core including a corehousing and a seal mounted on the core housing for sealing with respectto a structure adapted to receive the connector core, the structureincluding a shroud, a fiber optic adapter or a dust cap; and aturn-to-secure fastener mounted on the core for securing the core to thestructure, wherein the seal is positioned within an interior of theturn-to-secure fastener.
 14. The fiber optic connection apparatus ofclaim 13, wherein the seal is located at a rear third of a total lengthof the connector core, and wherein a ferrule is positioned at a frontend of the connector core.
 15. The fiber optic connection apparatus ofclaim 13, further comprising a keying rail integrated with the corehousing that extends forwardly from the seal and extends along at least25 percent of a total length of the core housing.
 16. A fiber opticconnection apparatus comprising: a fiber optic adapter including a mainbody having a first end defining a ruggedized connector port and asecond end defining a non-ruggedized connector port, the main body beingconfigured to be mounted in a mounting opening having a cross-sectionalarea less than or equal to 150 square millimeters.
 17. The fiber opticconnection apparatus of claim 16, wherein a ratio of the cross-sectionalarea of the mounting openings and a length of the fiber optic adapter inmillimeters is less than or equal to
 3. 18. The fiber optic connectionapparatus of claim 16, wherein the fiber optic adapter includes anexterior retention arrangement adjacent the first end, the exteriorretention arrangement including a snap-fit feature and also including aplurality of axial stops positioned about a circumference of the adapterbody.
 19. The fiber optic connection apparatus of claim 18, wherein theadapter body defines an internal holder for holding a ferrule alignmentsleeve.
 20. The fiber optic connection apparatus of claim 19, whereinthe adapter body includes a flange and an exterior threaded portion,wherein the mounting opening is defined through a wall, and wherein whenthe adapter body is mounted within the mounting opening the wall iscompressed between the flange and a nut threaded on the exteriorthreads.